urxvt256cd (1) - Linux Manuals

urxvt256cd: urxvt256c terminal daemon


urxvt256cd - urxvt256c terminal daemon


urxvt256cd [-q|--quiet] [-o|--opendisplay] [-f|--fork] [-m|--mlock] [-e|--eval perlstring]

urxvt256cd -q -o -f # for .xsession use


This manpage describes the urxvt256cd daemon, which is the same vt102 terminal emulator as urxvt256c, but runs as a daemon that can open multiple terminal windows within the same process.

You can run it from your X startup scripts, for example, although it is not dependent on a working DISPLAY and, in fact, can open windows on multiple X displays on the same time.

Advantages of running a urxvt256c daemon include faster creation time for terminal windows and a lot of saved memory.

The disadvantage is a possible impact on stability - if the main program crashes, all processes in the terminal windows are terminated. For example, as there is no way to cleanly react to abnormal connection closes, "xkill" and server resets/restarts will kill the urxvt256cd instance including all windows it has opened.


urxvt256cd currently understands a few options only. Bundling of options is not yet supported.
-q, --quiet
Normally, urxvt256cd outputs the message "rxvt-unicode daemon listening on <path>" after binding to its control socket. This option will suppress this message (errors and warnings will still be logged).
-o, --opendisplay
This forces urxvt256cd to open a connection to the current $DISPLAY and keep it open.

This is useful if you want to bind an instance of urxvt256cd to the lifetime of a specific display/server. If the server does a reset, urxvt256cd will be killed automatically.

-f, --fork
This makes urxvt256cd fork after it has bound itself to its control socket.
-m, --mlock
This makes urxvt256cd call mlockall(2) on itself. This locks urxvt256cd in RAM and prevents it from being swapped out to disk, at the cost of consuming a lot more memory on most operating systems.

Note: In order to use this feature, your system administrator must have set your user's RLIMIT_MEMLOCK to a size greater than or equal to the size of the urxvt256cd binary (or to unlimited). See /etc/security/limits.conf.

Note 2: There is a known bug in glibc (possibly fixed in 2.8 and later versions) where calloc returns non-zeroed memory when mlockall is in effect. If you experience crashes or other odd behaviour while using --mlock, try it without it.

-e, --eval perlstring
Evaluate the given perl code after basic initialisation (requires perl support to be enabled when compiling urxvt256cd).

This can be used for example to configure the internal perl interpreter, which is shared between all terminal instances, or create additional listening sockets for additional protocols.

The code is currently executed before creating the normal listening sockets: this might change in future versions.


This is a useful invocation of urxvt256cd in a .xsession-style script:

   urxvt256cd -q -f -o

This waits till the control socket is available, opens the current display and forks into the background. When you log-out, the server is reset and urxvt256cd is killed.


Both urxvt256cc and urxvt256cd use the environment variable RXVT_SOCKET to create a listening socket and to contact the urxvt256cd, respectively. If the variable is missing then $HOME/.urxvt/urxvtd-<nodename> is used.
Only used when the "--opendisplay" option is specified. Must contain a valid X display name.


urxvt256c(7), urxvt256cc(1)